Currently, sorting postal parcels at low throughput rates is not automated very much in sorting centers.
Such “low” throughput rates are rates that can be up to three thousand parcels per hour.
This type of sorting is generally performed manually by specialist operators who take the parcels one-by-one from a take point, who visually recognize a destination on a parcel that has been taken, and then, as a function of a certain sorting plan, determine the sorting bag into which the parcels should be put.
The sorting bags can then be recovered for delivery on a delivery round or “postman's walk” or be emptied for sorting the parcels in a new sorting pass.
Thus, the sorting rate at which parcels are sorted in such sorting centers depends essentially on the number of operators at work there and on their skill at sorting the parcels into the bags as a function of the sorting plan.
It can also be understood that the sorting plans changing at every sorting pass requires a substantial effort of concentration on the part of the operators, and that can give rise to sorting errors.
It should also be noted that sorting machines exist that are fully automated, that can be referred to as “shoe line sorters”, and that are used for sorting certain postal articles.
However, those machines are ill-suited for postal sorting at low throughput rates due to their costs being too high and to the floor area or “footprint” they occupy being too large.
Sorting equipment also exists for sorting articles into receptacles that are open at their tops as described in Document WO 2014/057182. That equipment comprises self-propelled shuttle cart and trolley assemblies that move independently, each conveying an article from a loading point to a receptacle, each of the shuttle cart and trolley assemblies having a carrying deck or rack for carrying an article, which deck is suitable for overlying the opening in the top of a receptacle.